Chain securing means for a lift truck



April 2, 1957 G.\F. QUAYL E 2,787,338

CHAIN SECURING MEANS FOR A LIFT TRUCK Filed Sept. 1. 1955 3 Sheets-Sheet1 l5 INVENTOR Geo 3c F ATTORNEY A rfl 2, 1957 G. QLUAYLE 2,787,338 CHAINSECURING MEANS FOR A LIFT TRUCK Filed Sept. 1. 1953- 3 Sheets-Sheet 2INVENTOR Gav/ e. F Qua /e ATTORNEY April 2, 1957 G. F. QUAYLE CHAINSECURING MEANS FOR A LIFT TRUCK 3 Sheets-Sheet 3 Filed Sept. 1. 195300000000 0000000000 O O i U INVENTQR Geoya 1 1 ATTORNEY CHAIN SECURINGMEANS FOR A LIFT TRUCK George F. Quayle, Philadelphia, Pa., assignor toThe Yale & Towne Manufacturing Company, Stamford, Conn., a corporationof Connecticut Application September 1, 1953, Serial No. 377,886 7Claims. (Cl. 187-9) This invention relates to industrial lift trucks ofthat class in which a lifting mechanism exerts a pull through flexiblemembers or chains to lift a load carriage. More particularly, myinvention relates to novel means whereby I secure the flexible membersin a truck of this class relatively to the load carriage.

Those skilled in the art will understand that the flexible members andlifting mechanism in this type of truck are sometimes subjected tounusual strains incidental to the operation or" the load carriage. Thus,the carriage may be subjected to a vertical impact, and in the priorart, this impact is transmitted to the flexible members and throughthese members to the lifting mechanism. Particularly when the liftingmechanism is a hydraulic ram, asudden closing of the valve that controlsthe ram fluid during descent of the carriage will cause a shock to betransmitted between the carriage and ram through the flexible members.This shock is detrimental to parts of the truck, and is extremely severewhen a heavy load is on the carriage.

Further, one flexible member or chain may .accept a greater part of theload than another to cause unequal stresses in the flexible members andlifting mechanism. As one instance in which this occurs in the priorart, the flexible members may be of slightly different lengths as aresult of wear, so that the longest member fails to take its full shareof the load. Also, the load carriage in some trucks may tend to apply agreater part of the load to one flexible member through a tendency ofthe carriage to cock in a transverse direction when supporting a loadthat is not symmetrical relatively to the carriage.

The unequal loading of the flexible members and the shocks transmittedthrough these members have presented a considerable problem to theindustry, and numerous solutions have been suggested. I believe theextremely novel means of my invention herein to be disclosed forms aconsiderable contribution to the art.

As an important feature of my invention, I apply the pull of theflexible members to the load carriage of the truck through yieldingstops on the carriage. By yielding of these stops, the pull applied tothe carriage through the flexible members is distributed between thesemembers, and thereby the flexible members do not transmit unequalstresses to the lifting mechanism. Moreover, the stops absorb shockswhen the carriage or flexible members are subjected to sudden impact.

I am aware that coil springs have been proposed for cushioning thelifting action of chains or cables relatively to a load member. However,it is not feasible to utilize coil springs for this purpose in a lifttruck, because these springs by yielding will effect an objectionableamount of lost motion betweeen the load carriage and flexible members.This is due to the characteristic yielding of a coil spring with amovement that is substantially proportional to the load applied to thespring. In addition, the heavy loads handled would require springs oftremendous size.

It is a particular feature of my invention that the 2,787,338 PatentedApr. 2, 1957 yielding stops allow relatively little lost motion betweenthe load carriage and flexible members, while enabling the flexiblemembers to accept heavy loads on the carriage with relatively littleshock. I form each stop as an attachment member, and this attachmentmember secures one of the flexible members for movement relatively tothe'carriage. On the attachment member is yielding means opposingmovement of the flexible member, with the yielding means so formed thatby yielding it enables the attachment member to accept, at a graduallyincreasing rate, forces that are applied between the carriage andflexible member.

As a further feature of my invention, I utilize in the yieldingattachment members a novel construction that is compact in a lateralsense. Those skilled in the art will understand that a coil spring,because of the size of spring that would be necessary to function underthe extremely heavy load handled by a lift truck, can not be readilymounted in the limited space at the back of the load carriage. Inaddition, a coil spring requires mounting means to make possible itsfunctioning. My novel yielding attachment members, because of theircompact construction, are very well adapted for mounting in the limitedspace provided, and eliminate all need for particular mounting means toobtain spring action.

As a more detailed feature of my invention, I mount each attachmentmember on the carriage merely through a pivot, with an elongatedyielding portion formed integrally on the member and contacting a partof the carriage at a considerable distance from the pivot, to opposemovement of the member on the pivot.

I I have thus outlined rather broadly the more important features of myinvention in order that the detailed description thereof that followsmay be better understood, and in order that my contribution to the artmay be better appreciated. There are, of course, additional features ofmy invention that will be described hereinafter and which will form thesubject of the claims appended hereto. Those skilled in the art willappreciate that the conception on which my disclosure is based mayreadily be utilized as a basis for the designing of other structures forcarrying out the several purposes of my invention. It is important,therefore, that the claims be-regarded as including such equivalentconstructions as do not depart from the spirit and scope of myinvention, in order to prevent the appropriation of my invention bythose skilled in the art.

Referring now to the drawings:

Fig. l is a side view showing my novel flexible chain securing meansembodied in a lift truck.

Fig. 2 is a view taken on the line 22 in Fig. 1.

Fig. 3 is a detail view similar to a part of Fig. 1.

To illustrate my invention, I show in the drawings a lift truck T havinga load carriage 10, and a hydraulic ram 11 acting through a pair ofchains 12 to lift the carriage 10. Actually, the load carriage 10 ismounted for vertical movement on the truck T through primary uprights 13and secondary uprights 14, with rollers 15 guiding the carriage 10relatively to the secondary uprights 14, and rollers 16 guiding theseuprights relatively to the primary uprights 13. The details of themounting for the carriage 10 are not important to an understanding of myinvention, however, and it is merely necessary to know that the loadcarriage is guided relatively to the truck for lifting movement.

The hydraulic lifting ram 11 is mounted relatively to the primaryuprights 13 through a lower cross member 17 on these uprights, and theram has a cross head 18 adapted to be extended upwardly by fluidpressure in the ram. At opposed sides of the ram 11, the cross head 18carries a pair of wheels 19 over which the lifting chains -12" arereeved. The chains- '12" are 'fixed"at"one end to a bracket 20 on theram cylinder 21 through adjustable anchors 22, so that in effect thechains 12. are anchored tothe primaryup rights ll Thechains 12 ex- -tenddownwardly frorrrthewheels' 19 to'opposed sides bf the loadcarriage"10-and*the crosshead 18 when extended by the Tamil-exerts apullthroughthe chains 12 to 'lift-the carriage 10.

' In-essence; the-construction Ihave thus far described isconventional.I shall now describe the exceedingly novelmeans whereby I secure thelifting chains to the load carriage.

-At the lower end of each lifting chain 12, I provide'a -novel-attachmer1t"member, indicatedgenerally by "the numeral 23 and best seenin Figs. land 3. The attachment members 23are pivoted'tothe loadcarriagefllt), and I-sh'ow*'for this purpose a"transve1'se'pivot-pin 25mouhting each member 23 on thecarriage through apair of 'brackets 24. Anarm portion 26 on each member '23 extends rearwardly from thepivot'pin25, and the chain '12-is'attached to this arm portion'26through'apin'27. The-pull of the liftingchains 12,"therefore,tendsto'rotate the"attachmentmembers 23 on their pivots 25.

l fo'rm integrally on "each member'23 an'elongated yielding portion orarmZS extending upwardly'awayfrom the pivot25. The upper-end 29-of thearm 28 is in contact with the rear face of apart 30'onthe load carriageat a point a considerable distance from the pivot 25. The yielding arm'28 thereby opposes rotation of the'attachment member 23 on itspivot'25; but the member 23 nevertheless can rotate through yielding ofthe arm- 28 in'response to the pull of its chain 12, with the chain andcarriage '10 "then'moving vertically relatively to one another.

Thearm portions 26 'on'the'members 23 are quite short 'relatively to theyielding arms 28, and thereby the -members ZS-occupy butlittle space uon the truck. 'In this arrangement, furthermore,- the movement of thearm portions '26 contributes very little lost motionbetween the carriage10 and'chains12despite a'considerable yielding movement of the arms 28.Through the'action of these arms 28 when a pull isexerted through thechains'12, I apply the pull -of'the chains to the carriage 10 at agradually'increasingrate. Stated inother words, the yielding arms '28oppose movementof the chains 12 relatively'to the carriage 10 with 'aresistance'that increases at' a "higher rate as the load is applied tothe attachment members.

Thef'particular yielding action of the arms28is extremely effective toenable the attachment members 23 to absorb vertical shocks between theload carriage 10 and the chains-12, and I thereby protect the liftingram 11 against shocks incidentalto the operation of the carriage. Sometendency'for the carriage 10 tobounce may occur when the shock is'verysevere, and to hold the attachment 'rnembers'23 withtheir arms "28against the part 30-when this bouncing action occurs, I form'on the-members 23 lugs '31 adapted to contact a lower portion of the carriage.

Because the attachment members 23 secure the lifting chains 12separately to'the load carriage 10, the carriage can,--of course,moveindependently relatively to -each chain. Therefore,'in thosecircumstances in which'one chain tends to accept more than its share oftheload, the attachment member for this chain will'yield to reducesomewhat the load on the chain,therebyincreasing the load on the otherchain by-a correspondingamount. 'By distributing the load betweenthelifting chains 12'in this way, I eliminate strains tending to occurinthe lifting mechanism when chains are not exactlythe same length, orwhen the carriage 10 has a tendency to code in'a transverse direction.

Ibelieve that the operation'and advantages of my novel flexible chainsecuring means will now be-clearly'understood, and that the veryconsiderable value of my in- 'vention'will' be fully" appreciated bythoseskilled in'the art.

I now claim:

1. In a lift truck of the class described, a load member mounted forvertical movement on the truck, a flexible lifting member for said'loadmember, means exerting a pull through said flexible lifting member tolift the load member, an attachment member pivoted to the load member,means attachingone end of the flexible lifting member in a positionrelatively to the pivot of said attachment member whereby pull on saidflexible lifting member tends to rotate said attachment member on itspivot, an integral yielding portion of said attachment memberopposing'the pivotal movement thereof relatively to the load member, andsaid portion being formed to yield upon the application of stress tosaid attachment member by said flexible lifting member. 7

2. Ina lift truck 'of'the class described, a load member'moiinfedforrnovement on the truck, a lifting means, a pair'of'flexible'lifting members through which the lifting means exerts a 'pullat eachside of the load member to lift the load member, attachment memberspivoted to the load member, means securing each flexible lifting memberto an attachment member at a point adjacent its pivotalinount'm'gformoving said attachment member relatively to the load memberin response to the pull of said flexible member, a yielding portionintegral with each attachment member so related to the pivotal mountingof's'aid attachment member as to contact a part on the load member tooppose the movement of each attachm'ent'member relatively to the loadmember.

"3} In a lift truck of the class described, a load member mounted forvertical movement on the truck, a flexible liftingmember for said loadmember, means exerting a pull through said' flexible lifting member tolift the load member, -an attachment member, means mounting saidattachment 'r'nember on the load member for movement relatively thereto,means attaching one end of the flexible lifting member to saidattachment member whereby pull on said flexible lifting member tends tomove saidattach- -mentmember on its mounting meansflan integral portionof said attachment member opposing said movement thereof relativelytothe load member, and said portion being formed to yield upon theapplication of stress to said attachment member by said flexible liftingmember.

4f'In' a "lift" truck of the class described, a load member mounted formovement on the truck, a lifting means, a 'pair' of "flexibleliftingmembers through which the lifting means exerts a pull at eachsideof the load member to lift the load member, a pair of attachmentmembers, means'mounting'each attachment member on the load member formovement'relatively thereto, means securing each flexible 'lifting'member to an attachment memher for movingsaid attachment memberrelatively to the load member in'response to the pull of said flexiblemember, a yielding portion integral with each attachment memberopposing-said movement of the attachment member on its mountingrelatively to the load member, and each yielding portion formed toaccept at' a gradually increasing rate the forces applied'theretothrough theattachment member.

5. In a lift truck of the class described, a load member mounted formovement on the truck, a lifting'm'eans, a pair of flexible liftingmembers through which the lifting means exerts a pullat each side of theload member to lift the load member, :said flexible lifting'memberswhen'unequally loaded tendingtoefiectunequalstresses insaid liftingmeans, an attachment member through'which each flexible liftingmemberisattached to the'load'member, means mounting each attachment member onthe load member for movement relatively to the load member in responseto the pull of itsflexible member, ayielding portion integral with eachattachment member contacting *a parton-the load member-to oppose saidmovement of each attachment member relatively to the load member,

and said attachment members acting through yielding of their yieldingportions to distribute between the flexible lifting members the loadapplied to said lifting members.

6. In a lift truck of the class described, a pair of uprights, a loadcarriage mounted for vertical movement on said uprights, a pair offlexible lifting members for said carriage with one flexible liftingmember secured to each side of the carriage, a hydraulic ram exerting apull through said flexible lifting members to lift the carriage on theuprights, an attachment member to which each lifting member is attached,means mounting each attachment member on the load carriage for movementrelatively to the carriage in response to the pull of its flexiblelifting member, a yielding portion integral with each attachment membercontacting a part on the load carriage to oppose said movement of eachattachment member relatively to the carriage, and said attachmentmembers moving slightly through the yielding of said yielding portionswhen the flexible lifting members are stressed in lifting the loadcarriage.

7. In a lift truck of the class described, a load member mounted formovement on the truck, a lifting means, a

pair of flexible lifting members through which the lifting means exert apull at each side of the load member to lift the load member, a pair ofattachment members each in the form substantially of a lever having athin yielding integral end portion, means securing one end of eachflexible member to one of said attachment members, and means pivotingeach attachment member near one end thereof on the load member forpivotal movement relatively to the load member in response to the pullof its flexible member and with its integral yielding portion contactinga part on the load member to oppose said pivotal movement of eachattachment member relatively to the load member.

References Cited in the file of this patent UNITED STATES PATENTS2,212,064 Elliott Aug. 20, 1940 2,241,798 Weiss May 13, 1941 2,354,178Ulinski July 18, 1944 2,595,120 Barnes Apr. 29, 1952

